A mobile-based intervention to improve adolescents' headache self-management Abstract Headache pain is a common and significant problem for adolescents (King et al., 2011). As headaches become more frequent and severe, the negative impact on happiness increases and adolescents report less satisfaction with their health and with their life (Sillampaa, 1983). There are a number of challenges associated with treatment, including adolescents' lack of consistent symptom tracking, medication overuse, and low self-efficacy for making lifestyle changes and for communicating about headaches. Self-management skills training addresses these types of challenges by increasing patients' self-efficacy for healthful behaviors (Burckhardt, 2005) and while it has been found to be successful with adolescents (e.g., Trautmann and Kroner- Herwig, 2009), it is not widely available. We propose to develop ThinkMe, a highly engaging mobile-based program that will help adolescents to make connections between behaviors and symptoms. The following specific aims were successfully completed as part of the Phase I investigation: (1) gather input from adolescents, caregivers, and experts; (2) produce content, design, and development plans; (3) produce the demonstration program; (4) assess whether the demonstration program is easy to navigate and relevant to adolescents and caregivers; (5) assess experts' beliefs about adoption, implementation, and maintenance of the program. Based on the results of the Phase I project, the mobile-based program will provide a state of the art pain tracker, a toolbox of tailored coping strategies, and evidence-based self-management skill-building information. The program will be tailored based on (1) the adolescent's demographic information, (2) how the adolescent feels each day, and (3) coping strategies that have worked in the past. In this way, ThinkMe will offer a maximally engaging way to help adolescents track their pain, make connections between lifestyle and pain, and learn key self-management skills. The specific aims of the Phase II are to: (1) create the program and (2) test its efficacy in a randomized controlled trial. We hypothesize that, compared to adolescents in the attention control group, adolescents who use ThinkMe will demonstrate: (1) increased coping; (2) decreased intensity of headaches; (3) decreased frequency of headaches, and (4) increased functioning and quality of life. Secondary outcomes are that adolescents will experience (1) decreased school absenteeism, (2) improved school functioning, (3) improved physical and psychosocial functioning, and (4) decreased health care utilization. The innovation of the current proposal is delivering an individually tailored, theory-driven, pain self-management intervention that can be widely disseminated with the novel use of technology to address self-management challenges associated with adolescent headaches. Successful completion of the aims of this Phase II proposal has the potential to have a significant public health impact by improving health, functioning, and quality of life for millions of adolescents with headache.